Sanding machine



Aug. 16. 1927. 1,639,216

r J. c. DE PENNING SANDING MACHINE Filed May 27. 1926 IN VEN TOR.

BY Jobn C De Perm/n] ATTO EY Patented Aug. 16, 1927.

UNITED. STATES JOHN C. DE PENNING, OE PORTLAND, OREGON.

' SANDING MACHINE.

Applicationifiled. May 27,

My invention relates to the rolls inasanding machine, used in f woodworking, which rolls are covered with felt or other resilient materials serving as acushion for-the sand paper. 1 V

It is common practice at the present time to bind said felt or other resilient material to the roll by a wire or by a canvas covering. fire is disadvantageous not only for the reason that groove. must be cut about the periphery of the roll into which said wire may seat, but also for the reason that such wire does not protect the felt against tearing. That is, a splinter which will tear through the sandpaper, will also tear the felt covering and require its replacement.

A canvas covering for the felt is disadvantageous because of its tendency to slip upon the felt, its bulk tends to stiffen or nullify the cushioning effect of the felt and also a canvas covering provides less frictional grip for the sandpaper or other abrasive material. 1

I have discovered that the advantages of both modes of binding the felt to the roll may be attained without involving the disadvantages of either, by binding the felt to the roll by friction tape. Said tape preferably is wound spirally about the roll for its entire length, the successive courses being arranged in abutment without overlapping, and the tape is preferably wound about the roll in two layers, one over the other, the layers being wound opposite hand to each other, so that the frictional contact ofthe overlapping tape portions will prevent the rotation ofv the roll from spreading the courses of binding tape apart.

My invention is hereinafter described in 40 greater detail, with reference to the accompanying drawings in which:

Fig fl is an elevation of the roll with a portion of the sandpaper lifted up and other parts shown broken away to show details of is the felt wrapping and its slack take-up devices Fig 2 is a fragmentary section taken thru the roll with the various layers shown dia- V grammatically, but with their thicknesses eX- aggerated; and

Fig. 3 is a fragmentary diagrammatic view illustrating the manner in which the friction tape is wrapped about the roll showing a portion of two layers, wrapped opposite hand, over the felt.

Sander rolls preferablyare made up of a 1926. Serial No. 112,064.

series of sheaves or drums a mounted abouta common central shaft 7) and provided with devices a for taking up the play or stretch in the various coverings therefor.

lVound about the periphery of the sheaves or drums a is a layer of felt (Z which provides resiliency for the sandpaper e which constitutes the active outer abrasive surface of the roll. Inasmuch as the roll attains considerable rotary speed the felt must be bound firmly to the sheaves or drums aand thus it is common practice either to bind the felt to the drums by piano wire, or by fitting over the felt a tight fitting wrapper-like canvas jacket.

My invention consists in substituting for said common binding means a continuously wound strip of friction tape f preferably arranged so that the adjacent edges of the succeeding courses are in abutment without overlaping; This eliminates any raised portions which would tend to cause the sandpaper 6 to become worn unevenl As shown in Fig. 3 I preferab y arrange the friction tape in two layers one over the other and wind the same opposite hand so that the adjacent surfaces of the frictional tape will stick together, to prevent the longitudinal displacement of the spiral courses under the action of the roll in operation.

In practice I find that friction tape approximately 1 inches wide is the most convenient width. Wider tape tends to buckle somewhat and narrower tape makes the wrapping operation more difiicult because of the greater number of courses to be laid. Friction tape whenrapplied is quite tacky and grips the upper surface of the felt so firmly that it is not displaced when the roll is used and, the adjacent surfaces of the layers of tape also tend to stick tightly together to prevent their relative slippage.

The fine dust thrown from the work operated upon, however, soon glazes the exposed surface of the outermost layer of tape, and allows the sandpaper to slide easily upon said surface and enables the slack taking up devices to function properly to prevent poaching or bulging of the sandpaper.

The glazed surface of' the friction tape, caused by dust lodging upon and adhering to said tacky surface, also forms a protecting sheathing for the felt which sheathing w1ll turn, effectively, splinters that will puncture and tear the sandpaper covering. That is, the exposed surface of friction tape soon glazes with use and presents virtually a tear-proof covering, but one which readily yields with the felt.

I claim:

1. In a sander roll of the character described, nieans for fastening a resilient covering to the drum portion thereof, comprising a relatively narrow strip of adhesive tape wound in a series of laterally adjacent convolutions about such covering, whereby each convolution or tape is adhesively bound to the covering to -forrn a continuous protective sheathing for such covering in which the convolutions' individually hold the covering.

2. In a sander rollof the character described, means for fastening a resilient covering to the drum portion thereof, comprising a relatively narrow strip of adhesive tape wound" in twos eries of laterally adjacent convolutions, one over the other and about such covering, and opposite hand to each other, whereby each convolution of tape in the inner series is adhesively bound to the covering, and each convolution of the outer series is bound to the inner series to foi'in a' continuous protective sheathing for such covering in which the convolutions individually hold the covering.

JOHN 0. DE PENNING. 

